As is known in the art, one type of infrared detector is an nBn or pBp structure having a bottom, or collector, semiconductor layer of a first type conductivity and an upper contact semiconductor layer of the same first type conductivity with a barrier layer sandwiched between the upper and lower semiconductor layers. In the case of the pBp structure the upper and bottom layers are p-type doped layers and in the cease of the nBn structure the upper and bottom layers are n-type doped layers. In one example, the upper and bottom layers are InAsSb, and the middle layer is AlAsSb. A reverse bias voltage is applied between the upper and lower layers. Thus, in the case of the nBn structure, the bottom layer is, for example, at ground potential and the upper layer is at a negative potential relative to ground potential. In response to infrared radiation, minority carriers, holes, pass between the upper and lower layers and through the barrier layer while the barrier layer prevents the flow of majority carriers. Unfortunately, the barrier layer can produce unwanted dark current